Everyday, billions of gallons of water are used in New York City for showers, filling up toilet bowls and consumption – and one government agency ensures that the entire system stays intact. The Department of Environmental Protection is responsible for maintaining New York City’s water supply, as well as the city’s air quality and excessive noise caused by everyday occurrences.

Here are 10 Secrets of the Department of Environmental Protection and New York City’s water supply.

10. The Department of Environmental Protection Used To Transport Waste by Train

Throughout most of New York’s sanitation history, waste was allowed to dumped into the ocean, gradually moving further and further out to sea. This rule changed when Congress banned ocean dumping in 1988, effective December 31, 1991, as a part of Congress’ 1972 Ocean Dumping Act. Once the ban was enacted, New York’s waste was transported via the “Poo-Poo-Choo-Choo” to Sierra Blanca, Texas. 45 trains per day traveled to the Texas town near the Mexican border.

According to Kate Ascher, author of The Works: Anatomy of a City, 25 tons of sludge were taken 90 miles south of El Paso and spread atop fields in one of the biggest sludge dumps in the world. Today, sludge is no longer sent to Sierra Blanca, and the last train was sent to Texas in 2001.